|
[Sponsors] |
![]() |
![]() |
#21 |
Senior Member
|
hm, Now I get it. I guess it would be ridiculous to use Euler to simulate turbulence.
|
|
![]() |
![]() |
![]() |
![]() |
#22 | |
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,830
Rep Power: 73 ![]() ![]() ![]() |
Quote:
This is an example of turbulence problem studied assuming no physical viscosity https://www.researchgate.net/profile...kman-layer.pdf |
||
![]() |
![]() |
![]() |
![]() |
#23 | |
Senior Member
|
Quote:
![]() Viscous drag needs a form of viscosity to be present, either real or numerical. In a direct Euler computation it is typically present in the form of numerical viscosity due to the numerical convective scheme. Thus, by nature, it cannot be actually accurate. But, imagine an aircraft at high speed with attached flow (low angle of attack). The numerical viscosity, in this case, will help you get lift and its induced drag, which is a form of pressure drag. If you know the lift-drag plot, you should know that the lift induced drag can be much higher than the base friction drag. The same, of course, won't work on a sphere or a cube. But, the idea of using Euler equations, is not much in getting an estimate of the drag, but in computing flows that, due to such feature, can return reliable evaluation of other quantities, like the lift, knowing that the neglected and/or miscomputed drag is not playing a dominant role in your computation. In a word... engineering. |
||
![]() |
![]() |
![]() |
![]() |
#24 |
Senior Member
|
In the base Euler/NS equations with an ideal gas law (remember that we are talking about the equations, not the real flow), there is no such distinction between supersonic or hypersonic. So, what I wrote just applies to any supersonic flow with such model equations.
|
|
![]() |
![]() |
![]() |
Tags |
euler equations, navier stokes equations, shock wave, turbulence |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Incompressible Euler Equations with SIMPLE method | yfjok22 | OpenFOAM Programming & Development | 1 | September 22, 2016 08:11 |
Normalization of eigenvectors of the Euler equations | bubble45 | Main CFD Forum | 9 | March 16, 2015 17:09 |
Exact solution - Euler equations | jakubstary | Main CFD Forum | 9 | May 6, 2013 18:14 |
Euler equations with heat conduction! | salem | Main CFD Forum | 10 | August 2, 2004 03:16 |
Euler equations? | Jan Ramboer | Main CFD Forum | 2 | August 19, 1999 01:58 |